Alkali metal salts of diglycol borates and methods for preparing the same



United Sttes Patent 3,087,960 ALKALI METAL SALTS OF DIGLYCOL BORATES AND METHODS FOR PREPARING THE SAME Marlene Denny, Honolulu, Hawaii, and Chien-wei Liao,

Beachwood, Ohio, assignors to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Filed Nov. 13, 1961, Ser. No. 152,070 9 Claims. (Cl. 260-462) This invention pertains to a method for preparing novel compounds containing boron and to the compounds so prepared.

The compounds prepared by the method of the present invention have the following general formula:

0 where R is an alkylene group, preferably an alpha or beta alkylene group, containing from 4 to 12 carbon atoms. The above general formula is intended to include compounds in which the alkylene radical may be the same, or it may be difierent for the two positions shown for R; for example, where one R is hexylene and the other R is butylene. M is an alkali metal such as sodium, potassium, or lithium.

These compounds find utility as intermediates for the preparation of final compounds useful as gasoline additives. The virtues of gasoline compositions containing the final compounds are set forth in co-pending application Serial No. 13,979, filed March 10, 1960, now US. Patent 3,013,046, assigned to our assignee. The disclosure of the latter co-pending application is incorporated herein by reference to the extent that may be required for a clear and complete understanding of the utility of the final compounds derived from the herein disclosed intermediates.

The method of the present invention for preparing the above-described boron compounds involves essentially a two-step process. The first step consists of forming a diglycol borate and the second step consists of forming the mono-alkali metal salt by reacting an alkali metal source with the diglycol borate. The latter compound has the following general formula:

' in which R is as defined heretofore.

is dissolved in a solvent and reacted with an alkali metal source at elevated temperatures. The source may be the pure alkali metal introduced in small pieces or in the form ofa fine dispersion, but preferably the reaction is conducted with the hydroxide of the alkali metal under conditions so that the water of reaction that forms is ice removed. The alkali metal hydroxide is preferably added as an aqueous solution but may be employed in the reaction if desired in pellet form. The water of reaction, as well as any water introduced with the reactants, may be removed by air blowing or simple boiling, but it is preferred to accomplish this by azeotropic distillation. The reaction temperature of the process is preferably held below 100 C. since diglycol borates have a tendency to decompose above this temperature. Accordingly, when the water of reaction is removed by azeotropic distillation in accordance with the most preferred embodiment of the process, it is desirable to select a solvent which azeotropes with water below 100 C. Illustrative examples of suitable solvents for this step of the reaction are benzene, toluene, xylene, cyclohexane, normal pentane, normal hexane, normal heptane, and naphtha blends boiling in the range of from to C.

The following examples illustrate the best mode contemplated for carrying out the method of the present invention, but are not intended to limit the invention in any way.

EXAMPLE 1(a) The diglycol borate was prepared from 52 g. (.5 M) of 2,2-di-methyl propanediol-1,3 and 15.4 g. (.25 M) of boric acid in 250 ml. of benzene. The two reactants were placed into a 1 liter three-necked flask, which was equipped with a mechanical stirrer and an azeotropic trap of 25 ml. capacity connected with a condenser. The reaction vessel was protected from the atmosphere by a drying tube containing anhydrous calcium chloride. The tube was attached to the top of the condenser. The reaction mixture was then heated at benzene reflux until water formation stopped. Theoretical amount of water to be formed: 13.5 ml. Amount of water found: 13.3 ml. or 98.8% of the theoretical. Most of the solvent was stripped off under slight vacuum. The residue was a white solid, which was recrystallized from naphtha. A white crystalline solid (36.6 g.) was obtained at M. Pt. C. (The diol had a melting point of 1121l6 C. and was insoluble in parafiinic naphtha, but has a limited solubility in highly aromatic naphtha.) This diglycol monoborate is unique in being a crystalline solid with a sharp melting point. The diglycol monoborates above and below this compound in the homologous series are liquids which cannot be recrystallized or are resinous in character due to the polymerization. Attempts to distill the homologous liquid borates causes them to revert to the triglycol diborate form. The compound of this example is unusual in that it can be isolated as a solid and purified by recrystallization, and is the only diglycol monoborate which, as far as is known, can be treated in this way. It can be used as the starting material for the following example:

EXAMPLE I(b) The reaction vessel was a 1 liter three-necked flask, equipped with a dropping funnel (with vapor by-pass), a mechanical stirrer and a condenser. A gas outlet fromthe top of the condenser was connected to a calcium chloride tube which was connected to a gas measuring device. This consisted of a one liter suction flask filled half-way with water. During the course of the reaction the water was pushed from this flask into a graduated 4. EXAMPLE I (c) 10.8 g. (.0 5 M) of the diglycol borate prepared as previously described in Example 1(a) were dissolved in 400 ml. of cyclohexane and placed in the reaction flask. The

cylinder by the hydrogen which was formed as the reaction 5 Solution was heated to reflux 1 8 4 1 g. of sodium hydroxide byproduct T water levels both the F and the pellets of 97% purity (.045 M) were dissolved in 7 ml. graduated eyhnder were equalized before talfmg readof distilled water and were then added dropwise from the The volume if watler z been dlsplacfed. addition funnel to the clear borate solution. A white, assumed to a v ume o y rogen fol-me at voluminous solid began to form immediately upon addiand 'f g e' M I d h 10 tion of the first few drops of base and water was distilled Metal 1e Sodium i 383 m t e over into the azeotropic trap. The addition of sodium reaeton {dong f t y 5: 0 hydroxide was completed after 10 minutes. Only 1.5 ml. toluene. T Vent. was eate h i of water had been collected at this point. After a total the boiling pomt was reached the measulmg heating period of 5.75 hours 6.7 ml. of water had been devlee was connected to the e Outlet we the ealemm 15 collected. Heating and stirrings were continued for an f tube the Y i: e bothf g a g e additional 7 hours, but no more water could be distilled eyhnder W equa lze and 3 O y out. The theoretical amount of water was'calculated to propanedlelle') borate (05,M).d1Sse1ved m 80 eelof be 7.0 ml.+8l ml. (.045 M formed during the reaction). toluene W added frem'tlie dmPPmg funnelever apenod Since the reaction mixture was extremely gelatinous, it of 40 mmutes' reaction mlxmre turned dark E may have a tendency to occlude some of the water, thereat t milky White P P? the formatlon of fore makingits removal by this method impossible. Heata gelatl neus Sohd (This was the only Instance. where t ing was discontinued, the 'flask contents were cooled to P of 9' dark e color "5 ebeerved' W room temperature and the white crystalline product was other dl'glyeole borates the .reaetlonmlxture turned k separated by suction-filtration. After oven-drying at 80 white as soon as some reaction product had been formed.) for 15 hours 1010 g of product was Obtained Hydrogen evlelufien proceeded .smeethly and theoretical yield was 10.7 g.98.8% yield. A neutral g z f g ilgg d i g ffeg amount of H2 to be equivalent was determined on the crude product accordorme C d 760 ing to the method outlined above. The value obtained The amount 0 P 2 g f an was 22261.6. Since this was considerably lower than mm=s4o a} 0 eeretlea the calculated value of 237.97 the'product was further The 'reaetlen mixture. was 3 e to room ttmpemlure purified by recrystallization from ethanol. It came out and was then filtered with suction. The filtration residue of this solvent in very fined wen defined needles. The E i g t g ie ffi? of 3 ether to 8 5 purified material was again'oven-dried at 80 It then ae rymg' e Wm e erys a l Pro ue was even me had a neutral equivalent of 232.0;L.5 which indicates a at 80 C. for 15 hours and weighted then 10.5 g.; 88.5% purity of 97 5% of the theoretical.

. Al fth tll ddt lltdfor The toluene filtrate was combmed wlth the ethyl ether 0 2 3 3;; e recrys a 126 pro uc (ca cu e washings and was then stripped to dryness on a rotary 4 evaporator under mild vacuum (300 mm.).

A neutral equivalent determination was run on the 40 Th. Fd. product. Samples (.3 g.) were weighted out accurately on an analytical balance, dissolved in 10 cc. of distilled Percent 0.- 50. 43 50. 03 water, heated briefly on a hot plate until the samples'were 3332 31%; 3: completely dissolved and then titrated with standard .1 PercentB 4.55 4.55 N HCl in the presence of 1 drop of methyl purple indi- 45 eater (titrated to Pale pupp 1e end pomt) The analyticalresults obtained for the products prepared Neutral equivalent found 235155135 by these two different synthetic routes agreed'very well Theoretical value 237.97 with those calculated for the postulated sodium derivative. Subsequently these derivatives were inspected by X-ray, Since the experimental value indicated that the product 00 t t was of 99.1% purity no further purification was attempted. i gg g rg g i ggfi g i gggf f'gg gg i ggg gg Analysis of the umecrystalhzed material: data obtained with both a boron and proton probe showed them to be highly tetracoordinated. The infrared studies FM support this conclusion.

I Sodium salts of butanedio1-2,3 borate and -1,3 as well :35:55 3-2.? 32g as pentanediol-2,4 borates were also prepared by the same PerccntNa. 9155 91 52 two methods. Their analytical data again checked ex- Percent B 55 48 cellently, with those of the postulated diglycol borate struc- All elemental analyses except Boron by Hufiman Microanalytical ture' The data of then preparations and analyses are Laboratories, Wheatridge, Colorado. tabulated in Tables I and II.

Table I PREPARATION AND ANALYSES 0F SODIUM DIGLYOOL BORATES (Na Method) Hr Per N.E. Percent 0 Percent H Percent Na Percent B Glycol 5111151 Rgciiyst.

1G 0 V. Th. Fd. Th. Fd. Th. Fd. Th. Fd. Th. Fd. Th. Fa.

numnediol-aa 2,450 2, 355 100 i-propanol..- 209.90 207.9 45.73 44.54 7.58 7.82 10. 11.45 5.15 5.15 Butancd1oll,3 2,240 2,150 95 ethan 209.9 202.15 45.73 44.53 7. 68 7.51 10. 95 11. 32 5.15 4.92 2,2-di-rncth. propaned10l-1,3 550 540 88.5 do. 237. 97 235.55 50. 43 49.95 8.47 8.43 9.55 9.52 4.55 4.48 Pentanediol2,4 1,120 82.9 d0 237.97 243.8 50.43 45. 55 8.47 8. 58' 9.55 9.54 4.55 4.91

H; volumes at STP.

Table II PREPARATIONS AND ANALYSES OF SODIUM DIGLYCOL BORATES (NaOH Method) H Per- N.E. Percent 0 Percent H Percent Na Percent B Glycol cent Recryst.

Yield Solv. Th. Ed 7 Th. Fd. Th. Fd. Th. Fd Th. Fd. Th. Fd.

Butanedi0l-2,3 15.5 12.4 99.0 i-propanol.-. 209.9 215.2 45.73 44.74 7.68 7.79 10.95 10.70 5.15 4.99 Butaucdiol-L? 178 98.0 ethanol 209.9 201.2 45.73 44.34 7.68 7.58 10.95 11.10 5.15 5.11 2,2-di-methyl propanedioll,3.. 6.7 93.4 0 237.97 232.0 50.43 50.03 8.47 8.33 9.66 9.99 4.55 4.55 Pentanediol2,4 6.8 90 i-propanol--. 237.97 235.2 50.43 46.45 8.47 8.55 9.66 9.15 4.55 5.02

*The theoretical amount of H20 is calculated as the sum of the water used to dissolve the sodium hydroxide and the water formed in the reaction. 'It is to be understood that various modifications of the forming a mono-alkali metal salt of a diglycol borate foregoing invention will occur to those skilled in the art upon reading the above description. All such modifications are intended to be included as may be reasonably covered by the appended claims.

We claim:

1. A method for preparing compounds of the following general formula:

wherein R is an alkylene group containing from 4 to 12 carbon atoms and M is an alkali metal, consisting of forming a mono-alkali metal salt of a diglycol borate compound of the general formula:

in which R is defined as above, by reacting said diglycol borate compound with an alkali metal source selected from the group consisting of an alkali metal in finely divided form and an alkali metal hydroxide.

2. A method for preparing compounds of the following general formula:

wherein R is an alkylene group containing from 4 to 12. carbon atoms and M is an alkali metal, consisting of forming a mono-alkali metal salt of a diglycol borate compound of the general formula:

O O R in which R is defined as above, by reacting said diglycol borate compound dissolved in a solvent which azeotropes with water under about 100 C. with an alkali metal hydroxide at the azeotropic distillation temperature to remove water from the reaction mixture.

3. A method for preparing compounds of the following general formula:

wherein R is an alkylene group containing from 4 to 12 carbon atoms and M is an alkali metal, consisting of compound of the general formula:

in which R is defined as above, by reacting said diglycol borate compound in an essentially inert non-aqueous solvent with a metallic alkali metal and removing the hydrogen formed.

4. Compounds of the following general formula:

0 R/ \B0R-0M wherein R is an alkylene group containing from 4 to 12 carbon atoms, and M is an alkali metal. 5. A compound having the formula:

which is a white crystalline solid having a melting point of C.

No references cited. 

1. A METHOD FOR PREPARING COMPOUNDS OF THE FOLLOWING GENERAL FORMULA: 